Researchers develop composting program with used coffee grounds

Thursday, May 22, 2014

MANHATTAN — An interdisciplinary Kansas State University research group is turning garbage into gourmet food.

The researchers are taking used coffee grounds from a campus coffee shop and using them as compost to cultivate gourmet mushrooms at the K-State Student Farm. By composting alone, 50 pounds a week — or about 30 percent of the coffee shop's total waste — has been diverted from landfills.

"The goal of the project is to demonstrate our potential at Kansas State University to initiate a successful closed-loop recycling and composting program that diverts waste from landfills and produce a beneficial product," Mladenov said.

While developing the compost program, the researchers made an important discovery: coffee grounds are a great compost for cultivating mushrooms, particularly gourmet mushrooms, such as oyster, shiitake and reishi. The U.S. gets nearly 45 percent of mushrooms from China, and there is a need for more local suppliers of gourmet mushrooms, said Kaley Oldani, master's student in civil engineering, Dublin, California, and the student leader for the project.

Oldani and other student team members recently traveled to Washington, D.C., to showcase their project at the EPA's 10th annual National Sustainable Design Expo for the People, Prosperity and the Planet competition. The university team previously received a $12,900 grant from the first phase of the competition, which features student-designed sustainable projects that benefit people, promote prosperity and protect the planet.

"It is important that Kansas State University students pursue sustainable projects because it is not only good for the environment, but it is good for our health since we benefit from clean air and clean water," Oldani said. "Sustainable projects also will help the university stay competitive with other institutions that are actively investing in sustainability and resource efficiency."

The project began in Mladenov's fall 2012 sustainable water and sanitation systems course when Oldani and other student teammates developed a closed-loop recycling and composting program. The students set up a new compost receptacle at Radina's Coffeehouse and Roastery in the university's Leadership Studies Building. They collected the used coffee grounds and took them to the K-State Student Farm and horticulture lab to work with Janke on mushroom cultivation.

"I am just really proud of our students taking the lead on this project," Janke said. "Several students involved with the student farm have been growing oyster mushrooms for sale in the past, but this grant allows them to take mushroom cultivation to a whole new level and collaborate with students and businesses across campus, while also continuing to do research on the best growing methods."

The coffee composting program coincides with the university's "One Stop Drop" push for single-stream recycling and has made a difference in waste diversion and landfilling costs, Mladenov said. The student team calculated that the university could save more than $45,000 per year in landfill fees by composting. Even greater savings could result if compost is used on campus grounds and agricultural areas as a soil amendment.

The research team plans to continue mushroom cultivation research. Because of the success with coffee grounds and mushrooms, the student team is studying other ways to grow gourmet mushrooms using materials such as wood chips and wood shavings leftover from projects in the university's department of architectural engineering and construction science.

"Ultimately, the students could turn this research into a small business venture that makes locally grown gourmet mushrooms available for sale at local farmer's markets or other venues that supply businesses like Radina's with the produce they use," Mladenov said. "Now that is a closed-loop system."

The project has received local support from the K-State Recycling Center and the School of Leadership Studies.

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At a glance

An interdisciplinary Kansas State University research group is taking used coffee grounds from a campus coffee shop and using them as compost to cultivate gourmet mushrooms at the K-State Student Farm.

Notable quote

"The goal of the project is to demonstrate our potential at Kansas State University to initiate a successful closed-loop recycling and composting program that diverts waste from landfills and produce a beneficial product."